Bicycle rear suspension system

ABSTRACT

A bicycle rear suspension system includes a front part including a top tube, a down tube, a head tube and a seat tube. A rear part of the bicycle rear suspension system includes two seat stays and two chain stays. The seat stays have first ends pivotally connected to the dropouts on the first ends of the chain stays and two second ends pivotally connected to a first end of a connection member at a first pivot point. Two second ends of the chain stays are pivotally connected to a bridge between the down tube and the seat tube. A second end of the connection member is pivotally connected to the top tube. A cylinder has a first end pivotally connected to the bridge and a second end pivotally connected to a mediate portion of the connection member at a second pivot point.

CROSS-REFERENCE TO RELATED APPLICATIONS

This Application is a Continuation of Application No. 12/073,717, filedon Mar. 10, 2008, and entitled Bicycle Rear Suspension System.

FIELD OF THE INVENTION

The present invention relates to a bicycle rear suspension system whichabsorbs shocks by pivoting the rear part of the bicycle frame.

BACKGROUND OF THE INVENTION

FIG. 8 to FIG. 11 show prior art to this invention. Prior art in thiscategory is comprised of a front section known as a front triangle and arear section known as a rear triangle. The rear triangle is connected tothe front triangle using any number of connection methods which may ormay not employ bearings, bushings, axles, clamps and flexible links. Ashock absorbing unit is connected between the front and the rear toallow the rear to move at a regulated rate with regard to the front. Anynumber of different connection methods for controlling the rate ofmovement can be used. The front section is typically but not in allcases comprised of a tube which carries the seat apparatus, a tube whichcarries the steering apparatus, and a tube which carries a crank andpedal assembly. These three tubes are connected together in any numberof different ways to form the front section. The front section generalprior art may have a single point of connection between the two (frontand rear) or multiple points of connection using any number of differentconnection methods and pivot and or link configurations. The rearsection is typically comprised of an apparatus/part to mount a wheel,considered in most cases the rear wheel, this apparatus/part is known asand will be referred to as a dropout. In most, but not allconfigurations, tubes will extend from the dropout forward, a typical(but not limited to) configuration incorporates a lower set of tubesconstructing an arm member known as the chainstay arms and an upper setof tubes known as the seatstay arms. Typically, but not in allconfigurations, these arms will provide, at the opposite end of thedropouts, a location to mount the rear triangle to the front triangle,and/or a variety of links or members, consisting of, or not, bearings,bushings, axles, and/or clamps and other possible apparatus to providerotation. Attachment to the front triangle can be at single or multiplelocation, dependant on the design, however there will be specifically asingle pivot that will control the arc/movement of the chainstay armsand/or rear triangle, that the pivot will be considered and referred toas the main pivot. The front triangle will have a location which isconsidered the main pivot, and the rear triangle will have a means forattaching to this location.

FIG. 12 discloses another conventional suspension system known toapplicant. This conventional suspension system is disclosed in U.S. Pat.No. 5,671,936, in which rear triangle movement is controlled by a shockabsorbing unit which starts its movement (is at its lowest potentialenergy state) at its shortest length between attachment points and growslonger as the rear triangle moves to a higher potential energy state.Such a shock absorbing unit is commonly referred to as an extension(pull) shock.

FIG. 13 discloses another conventional suspension system known toapplicant. The shown front section is known as a front triangle and arear section known as a rear triangle. The rear triangle is connected tothe front triangle using any number of connection methods which may ormay not employ bearings, bushings, axles, clamps and flexible links. Ashock absorbing unit is connected between the front and the rear toallow the rear to move at a regulated rate with regard to the front. Anynumber of different connection methods for controlling the rate ofmovement can be used. The front section is typically but not in allcases comprised of a tube which carries the seat apparatus, a tube whichcarries the steering apparatus, and a tube which carries a crank andpedal assembly. These three tubes are connected together in any numberof different ways to form the front section. The front section generalprior art may have a single point of connection between the two (frontand rear) or multiple points of connection using any number of differentconnection methods and pivot and or link configurations. The rearsection is typically comprised of an apparatus/part to mount a wheel,considered in most cases the rear wheel, this apparatus/part is known asand will be referred to as a dropout. In most, but not allconfigurations, tubes will extend from the dropout forward, a typical(but not limited to) configuration incorporates a lower set of tubesconstructing an arm member known as the chainstay arms and an upper setof tubes known as the seatstay arms and/or a variety of links ormembers, consisting of, or not, bearings, bushings, axles, links and/orclamps and other possible apparatus to provide rotation. However directconnection of chainstay members/rear triangle to the main/lower pivot ofthe front triangle is not made, instead, some means of links/alternativeconnection is used to divide the front section and the chainstaymember/rear section members. The front triangle will have a locationwhich is considered the main pivot or lower pivot.

FIG. 14 discloses another conventional suspension system known toapplicant. Shown is a front section known as a front triangle and a rearsection known as a rear triangle. The rear triangle is connected to thefront triangle using any number of connection methods which may or maynot employ bearings, bushings, axles, clamps, and flexible links. Ashock absorbing unit is connected between the front and the rear toallow the rear to move at a regulated rate with regard to the front. Anynumber of different connection methods, links, pivots, etc, forcontrolling the rate of movement can be used. However the shockabsorbing unit has one end that generally points to the tube thatcarries the crank and pedal assembly and is located generally in thatarea. The opposite end of the shock generally points in an upwarddirection. The shock is of compression (push) shock variety,specifically has a lower potential energy at the position which the endsof the shock are at the furthest distance apart. The front section istypically but not in all cases comprised of a tube which carries theseat apparatus, a tube which carries the steering apparatus, and a tubewhich carries a crank and pedal assembly. These three tubes areconnected together in any number of different ways to form the frontsection. The front section general prior art may have a single point ofconnection between the two (front and rear) or multiple points ofconnection using any number of different connection methods and pivotand or link configurations. The rear section is typically comprised ofan apparatus/part to mount a wheel, considered in most cases the rearwheel, this apparatus/part is known as and will be referred to as adropout. In most, but not all configurations, tubes will extend from thedropout forward. A typical (but not limited to) configurationincorporates a lower set of tubes constructing an arm member known asthe chainstay arms and an upper set of tubes known as the seatstay armsand/or a variety of links or members, consisting of or not, bearings,bushings, axles, links and/or clamps and other possible apparatus toprovide rotation.

FIG. 15 discloses another conventional suspension system known toapplicant. Shown is the front section known as a front triangle and arear section known as a rear triangle. The rear triangle is connected tothe front triangle using any number of connection methods which may ormay not employ bearings, bushings, axles, clamps and flexible links. Ashock absorption unit is connected between the front and the rear toallow the rear to move at a regulated rate with regard to the front. Anynumber of different connection methods for controlling the rate ofmovement can be used. However, the connection of the shock absorbingunit at the main frame shares a point of attachment which is alsoconsidered the main triangle main or lower pivot. The front section istypically but not in all cases comprised of a tube which carries theseat, a tube which carries the steering apparatus, and a tube whichcarries a crank assembly. These three tubes are connected together inany number of different ways to form the front section. The frontsection general prior art may have a single point of connection betweenthe two (front and rear) or multiple points of connection using anynumber of different connection methods and pivot and or linkconfigurations. However, such pivot location does not include the use ofbearings affixed into the section known as the front triangle. The rearsection is typically comprised of a location to mount a wheel,considered in most cases the rear wheel, a place to mount to the frontsection consisting or not of bearings, bushings, axles, standard linksand flexible links. This can be a single location or multiple dependanton the design, however specifically does not use a clamping mechanismthat clamps to an axle or shaft which extends through the front section.Moreover, the bearings, or bushings or other means of providingrotation(or other means of housing that means of rotation) are nothoused, or are a part of the front triangle.

FIG. 16 discloses another conventional suspension system 80 forbicycles, and includes a front part 81, a rear part 82, and a shockabsorbing unit 83. The front part 81 includes a top tube 811, a downtube 815, and a seat tube 813 connected to two respective second ends ofthe top and down tubes 811, 815. A bottom bracket 814 is connected tothe second end of the down tube 815 and the lower end of the seat tube813. The rear part 82 includes two seat stays 821 and two chainstays822. Two second ends 826 of the two chain stays 822 are pivotallyconnected to the rear of the bottom bracket 814 at the pivot point 818.A shock absorbing unit 84 has one end pivotally connected to a pivotpoint 817 under the top tube 811. The other end of the first cylinder841 is pivotally connected the two second ends of the seat stays 821 atpivot point 824.

When shocks are transferred to the rear wheel of the bicycle, the rearpart 82 is pivoted about the pivot point 818 and the two second ends ofthe seat stays 821 are pivoted about the pivot point 824 so that thecylinders 841 are operated to absorb the shocks.

SUMMARY OF THE INVENTION

The present invention relates to a bicycle rear suspension system whichcomprises a front part, a rear part and a shock absorbing unit. Thefront part includes a top tube, a down tube and a head tube which isconnected to two respective first ends of the top and down tubes. A seattube is connected to two respective second ends of the top and downtubes respectively. A bottom bracket is connected to the second end ofthe down tube and a lower end of the seat tube. The rear part includestwo seat stays and two chain stays which have two dropouts on first endsthereof. The seat stays have first ends pivotally connected to thedropouts. Two second ends of the two seat stays are pivotally connectedto a first pivot of a connection member at a pivot point. Two secondends of the chain stays are pivotally connected to the front part. Asecond pivot of the connection member is pivotally connected the frontpart. The shock absorbing unit includes a cylinder which has a first endpivotally connected to the front part and a second end pivotallyconnected to a portion of the connection member at a pivot point. Therear part is pivoted relative to the front part and the connection plateapplies a force to operate the cylinder to absorb the shocks.

The present invention will become more obvious from the followingdescription when taken in connection with the accompanying drawingswhich show, for purposes of illustration only, a preferred embodiment inaccordance with the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view to show the bicycle frame with the rearsuspension system of the present invention;

FIG. 2 is an exploded view to show the bicycle frame with the rearsuspension system of the present invention;

FIG. 3 is a side view to show the bicycle frame with the rear suspensionsystem of the present invention;

FIG. 4 shows that the rear part is pivoted relative to the front partand the rear suspension system of the present invention is activated;

FIG. 5 shows general upward forces that counteract rider downward forcesat the bottom bracket;

FIG. 6 shows the extension forces of the shock;

FIG. 7 shows the bearings set between the chain stays and cylinder;

FIG. 8 shows a conventional bicycle rear suspension system;

FIG. 9 shows a conventional bicycle rear suspension system;

FIG. 10 shows a conventional bicycle rear suspension system;

FIG. 11 shows a conventional bicycle rear suspension system;

FIG. 12 shows a conventional bicycle rear suspension system;

FIG. 13 shows a conventional bicycle rear suspension system;

FIG. 14 shows a conventional bicycle rear suspension system;

FIG. 15 shows a conventional bicycle rear suspension system; and

FIG. 16 shows a conventional bicycle rear suspension system;

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIGS. 1 to 7, a bicycle rear suspension system of thepresent invention comprises a front part 10, a rear part 20 and a shockabsorbing unit 30. The front part 10 includes a top tube 12, a down tube13 and a head tube 11 which is connected to first ends of the top anddown tubes 12, 13. A bottom bracket is connected to a second end of thedown tube 13 so as to be connected to a crank which is not shown. Aprotrusion 15 extends from a lower edge of the front part 10 and abridge 32 is connected to the bottom bracket and the down tube 13.

The rear part 20 includes two seat stays 21 and two chain stays 22 whichhave two dropouts on first ends thereof so as to be connected with anaxle of the rear wheel (not shown). The seat stays 21 have first endspivotally connected to the dropouts and two second ends of the two seatstays 21 are pivotally connected to a first end of a connection member33 at a first pivot point 35. The connection member 33 is composed oftwo plates between which the protrusion 15 is located. Two second endsof the chain stays 22 extend forward toward the front part. Second endsof the chainstays 22 are pivotally connected to the bridge 32 of thefront part 10 using an axle 39. The pivot 34 of the connection member 33is pivotally connected to the protrusion 15 of the front part 10 usingan axle 41. The pivot point 36 will be described hereinafter.

The shock absorbing unit 30 includes a cylinder 31 which is locatedwithin an area enclosed by the front part 10 and has a first endpivotally connected to the bridge 32 of the front part 10 using the axle39 and a second end of the cylinder 31 is pivotally connected to amediate portion of the connection member 33 at a second pivot point 36.

When shocks are transferred to the rear wheel, the rear part 20 ispivoted about the connection point of the chain stays 22 and the bridge32, the seat stays 21 pivot the connection plate 33 about the thirdpivot point 34, and the mediate portion of the connection plate 33applies an upward force f3 to operate the cylinder 31. The force f3 isshown in the FIG. 6. The cylinder 31 and the movement of the reartriangle act to absorb the shock and do not transfer shock to the frontpart 10 and the rider. Shown in FIG. 5, are force fl and force f2,between which a general range of upward force would be.

As shown in FIG. 2, two bearings 38 are located between ends of thechainstay 22 and mounted in the bridge 32, part of the front triangle10. Located at the end of the chainstays 22 are two clamping mechanisms40. The axle 39 is located through the clamping mechanisms 40 at theends of the chainstays 22, through the two bearings 38 and through theshock absorber end. This pivotal location is known as the main pivot ofthe system.

The rear suspension system of the present invention requires a fewernumber of parts and welding points so that the manufacturing andassembly costs are reduced.

While we have shown and described the embodiment in accordance with thepresent invention, it should be clear to those skilled in the art thatfurther embodiments may be made without departing from the scope of thepresent invention.

1. A bicycle frame comprising: a front part having a top tube extendingbetween a head tube and a seat tube and a down tube extending betweensaid head tube and a bottom bracket, said top tube having a protrusionextending therefrom and said down tube being coupled to a bridgeadjacent to said bottom bracket; and a rear suspension system including:a connection member connected pivotally to said protrusion; a rear partincluding two seat stays having front ends connected pivotally to saidconnection member at a location spaced from said pivotal connection tosaid protrusion to define a first moment arm of said connection member,and two chain stays having front ends connected pivotally to saidbridge; and a cylinder having an upper end and a lower end, said upperend being pivotally connected to said connection member at a locationspaced from said pivotal connection to said protrusion and spaced fromsaid pivotal connection to said front ends of said two seat stays todefine a second moment arm of said connection member, said lower endbeing pivotally connected to said bridge with said front ends of saidchain stays such that, when said rear part is pivoted upwardly relativeto said front part, said first moment arm is pivoted upwardly andthereby pivots said second moment arm upwardly to apply an upward forceto said upper end of said cylinder.
 2. The bicycle frame as claimed inclaim 1, further comprising at least one bearing disposed between saidbridge and said axle.